Silicon fertilization increases gas-exchange and biomass by silicophytolith deposition in the leaves of contrasting drought-tolerant sugarcane cultivars under well-watered conditions

CAMARGO, MÔNICA SARTORI; FERNÁNDEZ HONAINE, MARIANA; OSTERRIETH, MARGARITA; BOZZA, NATÁLIA GANZAROLI; DA MOTA SILVA, VICENTE; BENVENUTO, MARIA LAURA; DE ALMEIDA SILVA, MARCELO

PLANT AND SOIL

SPRINGER

Lugar: Berlin; Año: 2021 vol. 466 p. 581 - 595

0032-079X

Purpose Silicon (Si) fertilization provides benefitsto sugarcane. However, information remain scarceabout the relationship between Si fertilization, gasexchange responses, biomass and silicophytolithaccumulation in contrasting drought tolerant sugarcanecultivars under well-watered conditionsMethods Sugarcane cultivars (drought-tolerant anddrought-sensitive) were grown in pots containing soilwith low available Si and were treated (at rates equivalentto 0, 250, 500, 750, and 1000 kg ha−1 Si) with Si as silicate. The silicophytolith contents, morphotype descriptions, Si concentrations and gas exchange were evaluated in the top visible dewlap leaves. Stalklength and stalk biomass were also evaluated.Results The silicophytolith, Si contents, net CO2assimilation rate (A), plant transpiration (E), stomatalconductance (gs) and electron transport rate (ETR)of leaves and fresh biomass and length of stalksincreased linearly as functions of the Si applicationrate, independent of cultivar. RB86-7515 showedthe highest stalk length, fresh stalk and green leafbiomass, relative water content, and water potential,while RB85-5536 showed superior values for A, E,gs, and ETR. Conclusions Si fertilization improved photosynthesis,transpiration, stalk length, and stalk biomassproduction in sugarcane. The highest silicophytolithcontent was reflected in a diversity of silicifiedcells, which may favor a higher photosynthesis andbiomass. The increase of silicification in stomatacomplexes and trichomes with Si may be associatedto a higher Si availability and transpiration. Contrastingdrought-tolerant cultivars showed similar silicificationand gas exchange responses with Si. Consideringthese benefits, Si should be included in thefertilization program of sugarcane.